Method of insulating small conductors.



J. A. HEANY.

METHOD OF INSULATING SMALL CONDUCTORS.

7 APPLICATION FILED .IULY 22,1915- 1,198,350.

fiwerdrf 2 Patented Sept. 12, 1916.

asbestos or the like to fine ma UNIT D sTATEs PATENT oE IcE JOHN ALLEN HEANY, or NEW YoRK, N. Y., AssIeNoR To PATENTs EXPERIMENT CORPOR TION, O NEW YoRK, N. Y., A CORPORATION OF NEW YORK.

Specification of Letters Patent.

Patented Sept. 12, 1916.

Application filed July 22, 1915. Serial No. 41,245.

To all whom it may concern:

Be it known that I, JOHN ALLEN HEANY, a citizen of the United States, residing in the city, county, and State of New York, have invented certainnew and useful Improvements in Methods of Insulating Small Conductors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. J

This invention relates to a new and improved method of covering tenuous wires and electrical conductors with a uniform coating or sheath of fibers to form an effective insulation, and more particularly to the application of a sheath of short fibers of et wire or shunt Wire, in the form of a omogeneous, uniform, fire-proof and liquid-proof insulation of any desired thickness, and which will p issess all of the desirable characteristics of asbestos insulatlon as applied to heavy conductors by any of the known sulating factor.

methods, which, however, are wholly ineffective when attempted to be applied to soft, ductile and tenuous metal wires or filaments of small diameter because of the inability of such wires to withstand the stresses imposed-thereon during the direct application of the fibers thereto and the matting, smoothing and finishing of the fibrous coating.

, According to the present invention, it is possible to apply a practically uniform,-

homogeneous coating of fibersof any desired thickness or thinness to'wires ranging from .02 to .002 in diameter and to finish the coating thus applied by the addition bf a suitable binder and the subsequent condensing, smoothing and compacting of the coating to a homogeneous,-uniform, shell-like envelop that is highly flexible, extremely durable and possesses a uniformly high in- To this end, the invention contemplates the simultaneous rolling and longitudinal advancing together of the fine wire and a body ofcarded or straightened fibers, between longitudinally progressing and laterally reciprocating surfaces, whereby the fibers are uniformly twisted and matted about the rotating and advancing wire, and subsequently applying a suitable binder to the coating of fibers, and if desired, thereafter subjecting the coated-wire to a further rolling and longitudinally advancing opera- I tion, whereby the coating is smoothed, con- A suitable form of apparatus for carrying. out the invention is illustrated in the accompanying drawing, in which the said apparatus is represented more or less diagrammatically in side elevation.

According to the prior practice of insulating fine wires of the so-called magnet or shunt type, in which the'tenuous and fragile character of the wires precluded the application of any heavy stresses thereto, it has been customary to apply either a varnish or enamel-like coatingto the surface of the wire, or to cover the wire with a winding of spun silk or similar thread, but such insulating sheaths or coverings are unsatisfactory, for the reason that those of the first class are extremely, liable to rupture and do not possess high insulating values, and those of the second class are expensive, diificult of application, and the coverings being loosely applied, lack uniformity, homogeneity and material insulating qualities per 86, and are, moreover, so easily displaced as to require .the greatest care in manipulating the covered wire. The present invention avoids all these difficulties and enables even the finest commercial sizes of wires and similar electrical conductors to be quickly, effectively and cheaply covered by a uniform, homogeneous coating of asbestos or the like, which proves quite as efiective, in all respects, as similar coatings applied to larger sized conductors by any of the old known methods. Incidentally, it may be remarked that the present method is not applicable to wires or conductors of larger sizes than say No. 28 Brown & Sharp gage because of the fact that it is impracticable to roll and twist such Wires about their longitudinal axis in the application of the fibers thereto, without nate directions, the action in no wise impairs the structure or consistency of the wire, but leaves the wire in practically the same condition as before such treatment.

As indicated, the accompanying drawing shows a simple and effective form of apparatus for carrying out the invention, although it is to be understood that various other forms of apparatus may be employed without departing from the essential features of the new method.

Referring to the drawings, 1 indicates the dofi'er cylinder of an ordinary carding machine, siid cylinder having its surface provided with the usual form of .card clothing, which takes up the straightened fibers of asbestos and the like from the main cylinder of the machine and delivers them to a roll 2 located adjacent cylinder 1 and having its surface preferably covered with corduroy or similar fabric which takes up the straightened fibers in the form of a sliver or web. Preferably located above the roll 2 is a spool 4 carrying the fine wire w, which latter passes through apigtail or guide ring 5 and thence downward under the roll 2.

In front of the roll 2is located a rub roll or condensing apparatus 3, which may be of any standard or appropriate type and, as shown, consisting of two continuous belts, the inner adjacent reaches of which travel in the same direction and contiguous to each other, said belts being reciprocated laterally in opposite directions. As the wire and the straightened fibers pass from the roll 2 between the belts or aprons of the rub "device, the portion of the wire engaged by the belts is rolled or twisted about its longitudinal axis and simultaneously advanced in a longitudinal direction between the belts. The lateral reciprocation of the belts rolls and twists the fibers uniformly about the wire and the forward movement of the belts further compacts and smooths the fibrous coating into a uniform layer over the entire surface ofthe wire. As the wire passes from the rub roll device the coating thereon is preferably sprayed or impregnated with a suitable binding agent supplied from a tank o by means of a valved pipe 7. The bindj ng agent may be of any suitable or desired character, and may, in addition to locking and cementing the matted coating fibers to the wire, also serve as a liquid-proofing medium. V

In order to further unify and homogenize the insulating sheath or coating, the coated wire is preferably passed through a second rub device 3, 3', where it is subjected to a further rolling action while being fed forward between the belts of said device.

After leaving the second rub-roll device, if it is found desirable, the coated wire may pass through a polishing die 9, of any suitable form, whence it passes around a tension roll 10 and thence to a storage or re-winding reel or roll 11, which spools the covered wire in condition for commercial use.

In the practical application of the process as described by means of a machine substantially like that illustrated, it has been possible to apply an absolutely uniform, homogeneous insulating sheath of asbestos fibers,

with a suitable impregnating medium, to I coat wires as small as .002, the finished wire being delivered from the machine at the rate of several feet per minute, without any impairment whatever of the structure of the wire and with a remarkable freedom from tendency of the wire to break, kink or buckle. It was also found that by properly regulating the feed of the fibers tothe cardin carding the fibrous material, feeding the carded fibers and the wire between longitudinally progressing and laterally reciprocating surfaces to uniformly mat and wind the fibers about the wire and applying a suitable binder to the fibrous coating.

3. The method of covering fine wire with a fibrous sheath of insulation, which consists in simultaneously rolling and advancing the wire and the body of carded fibers together, applying a suitable binder to the fibrous coating, and again rolling and advancing the fiber-coated wire between longitudinally progressing. and laterally reciprocating sur-' faces.

4. The method of covering fine wire with a fibrous sheath of insulation, which consists in carding the fibrous material, feeding the carded fibers and the wire between longitudinally progressing and laterally reciprocating surfaces to uniformly mat and wind the fibers about the wire, applying a suitable binder to the fibrous coating, and

smoothing and polishing the coating on the wlre.

- In testimony whereof I aflix my signature, in presence of two witnesses.

JOHN ALLEN HEANY. Witnesses:

VIOLA B. SMITH, T. R. HILTON. 

